Near this structure are the entrances of the city’s ancient water systems, parts of which seem to be from David’s time. Some statements in the Bible about Jerusalem’s water-tunnel system have given rise to questions. For instance, David told his men that “anyone striking the Jebusites, let him, by means of the water tunnel, make contact” with the enemy. (2 Samuel 5:8) David’s commander Joab did this. What exactly is meant by the expression “water tunnel”?

Scholars have long recognized that the ancient city’s main source of water was the Gihon spring. It was located outside the city walls but close enough to allow for a tunnel and a 36-foot-deep [11 m] shaft to be excavated, which would enable the inhabitants to draw water without going outside the protective walls. This is known as Warren’s Shaft, named after Charles Warren, who discovered the system in 1867. But when were the tunnel and the shaft made? Did they exist in David’s time? Was this the water tunnel used by Joab? Dan Gill answers: “To test whether Warren’s Shaft was in fact a natural sinkhole, we analyzed a fragment of calcareous crust from its irregular walls for carbon-14. It contained none, indicating that the crust is more than 40,000 years old: This provides unequivocal evidence that the shaft could not have been dug by man.”